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Impairment of assets (Tables) | 12 Months Ended
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Dec. 31, 2020
Disclosure of impairment of assets [Abstract] |
Disclosure of significant unobservable inputs used in fair value measurement of assets | The Corporation utilized the Corporation's long-range forecast and the following key assumptions in 2019 compared with 2016 assumptions, which was the most recent detailed valuation:
| 2019 | 2016
Mid-Columbia annual average power prices | US$30 to US$42 per MWh | US$22 to US$46 per MWh
On-highway diesel fuel on coal shipments | US$2.35 to US$2.40 per gallon | US$1.69 to US$2.09 per gallon
Discount rates | 5.2 to 6.4 per cent | 5.4 to 5.7 per cent

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- Definition The disclosure of significant inputs for which market data are not available and that are developed using the best information available about the assumptions that market participants would use when measuring the fair value of assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2019-01-01 -Paragraph 93 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2019-en-r&anchor=para_93_d&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition Disclosure of impairment of assets [Abstract] + References No definition available. + Details
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